Method of drilling and reaming barrels for firearms.



G. E. AVIS.

METHOD OF DRILLING AND BEAMING BARRELS FOR FIREARMS.

APPLICATION FILED JUNE 21 Patented Apr. 4, 1916.

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Application filed June 2'1, 1915. Serial l lo. 35,218.

To all whom 25' may concern.

Be it known that l, Gnonon E. Avis, a

citizen of the United States, residing at New Haven, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in the Methcd of Drilling and Roaming Barrels for Firearms, of which the followingds a specification, referencebeing had therein to the accompanying drawings. My invention. relates to a new and improved method of drilling and reaming barrelsior fire arms, and has for its object, among other things, to provide means for boring out a gun barrel in the shortest possible time, with the minimum waste material.

To these, and other ends, my invention consists in the method of drilling and reaming barrels forfire arms, particularly set forth in the following specification and illustrated in the drawings accompanying the same, in which- I Figure 1 is a longitudinal sectional" view of a gun barrel showing the same after it has been drilled; and Fig. 2 the same barrel after the reamin operation with the bore finished.

Heretofore it has been the practice to barrel with a drill that enters at one end and cuts the hole through the entire length thereof. This method has proven objectionable -for many reasons, among others, beingthe fact that the drill does not run straight and is considerably out of true when it comes through the opposite end of the barrel. This necessita tes the making of the rough barrel considerably larger than ifthe drill run. straight tl'irough, the barrel isfinished with the drilled hole as the center. The drill also frequently drills a hole that is bowed between its ends. T his also must be guarded against, usually by using a drill smaller than would otherwise be desirable, as in every case the hole -is reamed after being drilled and enough material must be barrel to provide a smooth and straight hole or bore from end to end.

With the method above described, having the objections indicated, as well as many others, the drill works only from one end of the barrel, and hence much time is required to perform the drilling operation; the drill is much longer than the barrel itself, and by reason thereof it is impossible to Specification of Letters Patent.

left in the rough.

Patented Apr, 4, 1916.

drill a straightfliole its entire length; and I agaiinas'the rough barrel must be made suiiiciently large to provide for the'imperfeet drilling thereof and be finished 'with the drilled hole as the .center instead of the 7 actual center of the rough barrel, much r'naterial and time is thereby wasted. K

I have over-cor call of these objections in my improved method by forming the rough gun barrel of substantially its completed size and shape, leaving ohlysutlicient stock thereon "for a finishing cut afterthe hole is bored, and in some cases, with som'ebarrels, even this is not necessary, by usinga plurrality or comparatively short drills, which;

same time, and afterward Withdrawn and two new drills substituted of slightly are fed into the barrel from both'ends at the diameter until they meet in the longitudinal center or the barrel, after which the drilled hole is reamed out to its finished size.

In the drawings, the numeral 1 designates the gun barrel, and in Fig. 1 the same is shown after it has been drilled, the holes being thefirst ones bored, followed successively bythe holes, 3-3, ii-+4, 5-5,- 6--6 and 7.?, each being slightly ameter thanthe preceding holed The difference in the diameters of these holes is an aggerated in the drawing for the purpose of clearness in illustration. In practice they difier in diameter not more than one'thousandth of an inch, or slightly more, sired.

. It is almost impossible to have a :drill run straight and true in drilling out a gun barrel, but my method if the drill does run out of true, the extent of its inaccuracy will be smaller in dii b ll one-half of what it would be under the old method, as the hole only extends half war through the barrel instead of through la. entire length and the greatest oilset is near the center of the barrel where the diameter of the holes the smallest and there is sufiicient material for the reamer that passes through the barrel to produce the finished bore.

With my method the drills are comparatively short and hence the liability to break or spring is reduced to the minimum, and as the barrel is bored from both ends at the same time, the amount of time required to drill it IS very materially racy of the drilled hole is near reduced; inaccu-- the longitudinal center of the barrel Where the holes are the smallest'in diameter; each successive drill is guided in the hole made by the preceding drill, and being of slightlysmaller diameter the probability of its traveling out of its true line is reduced to the minimum; and again, the hole being drilled from both ends concentric with the barrel itself, permits the rough barrel to be made substantially the same size and shape as the finished barrel, thereby saving material and labor in the finishing process. 7

Having described my invention, What I claim as new and desire to secure by Letters Patent, is k I l. A new and improved method of drilling barrels for fire arms, consisting in drilling the barrelfrom both ends by a succession of drills of progressively smaller diameter.

2. A new and improved method of drilling barrels for fire arms, consisting in drilling the barrel from both ends at one and the same time by a succession of drills of progressively smaller diameter.

I 3. A new and improved method of 'drilling and reaming barrels for fire arms, con- 'sisting in drilling the barrel from both ends at one and the same time by a succession of drills of progressively smaller diameter and reaming the drilled holes so as to produce a straight hole of uniform diameter.

In testimony whereof I have hereunto affixed my signature.

GEORGE E. AVIS. 

